Human Cytomegalovirus (HCMV) is a highly specific β-herpesvirus. Primary infection of healthy children and adults is usually asymptomatic, with a minority of cases developing a mononucleose-like syndrome. In contrast, congenital infection (U.S. 0.2%-2.2% per live birth; aprox. 40,000 per year) leads to several neurological defects in 10-15% of infected neonates. Immunocompromised patients represent another host group facing serious disease complications caused by HCMV infection or reactivation of a persistent infection. Up to 40% of the AIDS patients, for example, develop retinitis, pneumonitis, gastroenteritis or disseminated HCMV disease. In addition, allograft recipients (20,000 allograft transplantations per year in the U.S.) are often infected (or superinfected) by virus from the transplanted organ.
Clinical symptoms in the posttransplant period include prolonged fever, leukopenia, thrombocytopenia, atypical lymphocytosis, elevated hepatic transaminases and decreased graft survival. In bone marrow transplantations, HCMV infection is associated with high mortality rates (80-90% for untreated HCMV pneumonia).
Current approaches to develop therapeutics against Cytomegalovirus (CMV) have focused on antiviral agents per se; for example viral polymerase inhibitors. In fact, high mortality rates have been dramatically reduced by new antiviral agents. Current CMV therapeutics possess severe drawbacks, however. For example, Fomivirsen (Vitravene, formerly ISIS 2922) is typically administered by injection directly into the eye every 2 or 4 weeks. Ganciclovir is available for intravenous (Cytovene) or oral administration, and as an implant in the case of retinitis; unfortunately, toxic complications including leukopenia and thrombocytopenia frequently develop. Foscarnet (Foscavir; phosphonoformic acid), another antiviral agent, exhibits considerable renal toxicities and is only available in intravenous form (which is also true for Cidofovir (Vistide), another CMV therapeutic). In addition, CMV replication resumes soon after Ganciclovir and Foscarnet treatment is halted. Finally, Ganciclovir- and Foscarnet-resistant strains of CMV are emerging.
Although treatment of HCMV-induced disease has been improved with these inhibitors of the viral polymerase and preemptive or early antiviral therapy in transplant patients, there is a need in the art for a new class of HCMV therapeutics with better oral bioavailability and reduced toxic effects. This is especially true in the treatment of retinitis in AIDS patients, where CMV infection must be controlled for long periods of time.
Recent research has revealed how cells communicate with each other to coordinate the growth and maintenance of the multitude of tissues within the human body. A key element of this communication network is the transmission of a signal from the exterior of a cell to its nucleus, which results in the activation or suppression of specific genes. This process is called signal transduction.
An integral part of signal transduction is the interaction of cytokines, their receptors, and intracellular signal transduction molecules. Cytokines serve as messengers that bind to receptors on the surface of a target cell. As a result of the binding, the receptors activate a cascade of downstream signaling molecules, thereby transmitting the message from the exterior of the cell to its nucleus. Signal transduction to the nucleus modulates specific gene expression (i.e., transcription and translation), which results in either the upregulation or downregulation of specific proteins that carry out a particular biological function.
Viral infection disrupts normal signal transduction, which leads to cellular malfunctioning resulting in a disease state. Specifically, interference of HCMV with relevant human primary cells is necessary for the virus to create an environment that allows it to grow and replicate, and in turn cause disease in the infected individual. Current research efforts have failed to elucidate all the specific intracellular signal pathways affected by HCMV infection, however. Discovery of the signal transduction pathways and specific intracellular signal transduction molecules affected by CMV infection would represent a tremendous advance in the understanding of the induction and progression of CMV infection processes and provide new avenues for the development of a novel class of effective therapeutics for the treatment of CMV.
Thus, object of the present invention is to provide methods for detecting, preventing and/or treating Cytomegalovirus infection and/or associated diseases, methods for the identification of compounds useful for preventing and/or treating Cytomegalovirus infection and/or associated diseases and for regulating the production of Cytomegaloviruses.
The object of the present invention is solved by the teaching of the independent claims. Further advantageous features, aspects and details of the invention are evident from the dependent claims, the description, and the examples of the present application.